Method and apparatus for manufacturing a substrate with a magnetron sputter coating

ABSTRACT

Manufacturing a coated substrate by magnetron sputtering includes cyclically moving the magnetron magnetic field pattern along a sputter surface, positioning a substrate to be coated a distance from and facing the sputter surface, moving the substrate along the sputter surface and varying an amount of material deposited on the total substrate per time unit from the magnetron source that is cyclically and phase-locked with the cyclically moving magnetron magnetic field pattern.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. patent application Ser. No. 10/530,994filed Sep. 7, 2005 and now U.S. patent Ser. No. ______, which was a 371application on international application PCT/CH2003/000674 filed Oct.15, 2003, which claims priority on U.S. provisional patent application60/418,542 filed Oct. 15, 2002, which priority is repeated here and allthree prior applications being incorporated here by reference.

FIELD AND BACKGROUND OF THE INVENTION

The present invention concerns a procedure in accord with the principalconcept of the claims.

WO 00/71774 of the same applicant as of the present application,discloses, that in a case of a sputter source, which has been“operational point stabilized” and is used in a reactive coatingprocess, at which said source, a planar substrate, situated parallel tothe sputter surface, can be moved in a circular path relative to thesputter surface to compensate for a so-called “stringy effect”. The term“stringy effect” is to be understood as an unequal apportionment of thequantity of material deposited on the said substrate in the direction ofthe movement of the substrate. This is essentially disturbing in that,because of the circular path, and because of the planar state of thesubstrate, different substrate zones build themselves parallel to thesputter surface as the deposition experiences different distances ofseparation and angular relationships with the sputter surface. Thedifferent coating rates which evolve from the above, extending in thedirection of motion of the substrate, are compensated for in that,synchronously with the substrate movement over the sputter surface, thetreatment atmosphere is modulated in accord with a given profile.

In addition, magnetron sputtering is known. In this process, by means ofthe sputter surface, one or more, preferably self closing, loops oftunnel shaped magnetic fields form from the sputter surface, aligningthemselves out of and within this said surface. Because of the electrondrop known in a magnetron-magnetic field interacting with an appliedelectrical field, there arises in the area of the said tunnel shapedmagnetron magnetic field pattern, an increased density of plasma, which,on its own, leads to an increased sputter rate in this zone. The sputterrate achieved by means of magnetron sputtering is essentially greaterthan sputtering which is not supported by a magnetic field. Because,however, along the magnetron magnetic field pattern, an increasedsputter rate occurs, in the sputter surface eroded grooving appear,which are generally known as a “race track” presentation. This so-calledrace track then leads to a circumstance, wherein a poor usage of thesputter target material results.

Primarily based on these grounds, one comes to the conviction, that themagnetron magnetic field pattern, while the source is active, must bemoved above the sputter surface and thereby, to the greatest possibleextent, distribute an increased sputtered material deposition below thesaid pattern and consequently over the entire sputter surface in thegiven time. Thus, it can be additionally achieved, that, in a case ofreactive magnetron sputtering with a movable magnetic field pattern, anessentially reduced poisoning of the target, that is to say, forming adisturbed coating of target surface areas, which have poor electricalconducting interbindings which are needed for a successful reactiveprocess. In the case of reactive coating processes, that is, theproduction of a coherent layers, for example, starting from a metallictarget in the presence of a reactive process gas, possibly oxygen, forthe deposition of metal oxide layers, because of a mobile magnetronmagnetic field pattern, a uniform, cyclic erosion of the sputter surfaceoccurs, whereby a disturbance of the coating, here an oxide layer, isconsiderably reduced. This action leads to increased process stability.On this account, it is generally not necessary to provide an operationalpoint stabilization by control, where reactive magnetron sputtering witha mobile magnetron magnetic field pattern is carried out.

Normally, the cyclic movement of the magnetron magnetic field patternalong a sputter surface is realized in one or two dimensions. Thus itbecomes possible, for example, in the case of a long, rectangulartarget, that a pattern which forms a closed loop can be cyclically movedback and forth in the longitudinal direction of the target, whereby thismovement is cyclic in one dimension. Again, in the case of a targetarrangement which is extended into two dimensional directions, then themagnetic field pattern is cyclically reciprocating in both directions,which leads to a movement path of the magnetic field along the sputtersurface in accord with a Lissajous-figure. The cyclic magnetic fieldpattern movement can be attained, especially in the case of roundtargets, principally by means of a rotational movement, which can beeither in circle form or as an oscillating, pendular motion, which takesplace in relation to a vertical axis from the sputter surface. In thisoperation, it is immediately obvious, that in regard to this said axis,the magnetic field pattern must not be circular.

Magnetic field patterns which are rotational, are already known, whichare simply mirror-symmetric to an axis in a plane parallel to thesputter surface. Such magnetic fields are, for example, in the form ofhearts, apples, kidney and the like as may be taught by the followingU.S. patents:

U.S. Pat. No. 4,995,958

U.S. Pat. No. 5,252,194

U.S. Pat. No. 6,024,843

U.S. Pat. No. 6,402,903.

Further, the shapes may be double mirror-symmetric in form, as seen inthe figure “8”, in accord with U.S. Pat. No. 6,258,217, thusmirror-symmetrical to two axes, which are perpendicular to one anotherin the said plane.

In addition to the above, a process is known, of moving the substrate,which is to be coated, during the coating procedure, along the sputtersurface with the mobile magnetron magnetic field pattern. This isespecially advantageous, for the so-called “Batch-Equipment”, whereinseveral, even a multiplicity of substrates are coated during oneequipment coating cycle.

The requirements of the local apportionment of the thickness of thecoating, that is to say, the requirements on the off-sputtered materialsalong the substrate surface, are in many cases, very high. In the caseof optical coatings, for example, such as found in applicationsregarding components for projection displays, it is necessary thatcoated substrates have a layer-thickness apportionment, which deviatesat the most, 1% from the average thickness for an area of 1000 cm², inorder to assure a favorable economic production of coatings consistingof only few layers up to perhaps 50 layers. In the application of socoated substrate for optical data transmission, then coating thicknessdeviations of, at the most, 0.01% in reference to the average layerthickness are demanded. In this case the produced surfaces would be atthe least, 10 cm². In this latter case, onto such substrates, up to morethan 100 individual coatings may be laid in processes with durationsbetween 12 and 50 hours.

Fundamentally, the basics lie therein, in that by the use of a magnetronsource with a sputter surface, wherein a magnetron magnetic fieldpattern is cyclically moved along a sputter surface, and substrate isspecifically distanced from the sputter surface and moved thereover, onewill gain the largest possible substrate surfaces having the smallestpossible deviations of the coating thickness—in the case of reactivecoating processes of the deposited quantity of the off-sputteredmaterials—along the substrate surface. When we speak, in thisconnection, of the “coated substrate surfaces”, we mean the entirecombination of such surfaces of a plurality of batch-treated smallsubstrates or the surface of one large substrate.

We speak in the following in regard to the apportionment of the coatingthickness and understand, in this respect, the apportionment of thequantity of off-sputtered materials onto the substrate surface forreactive processes, which, in the case of said reactive processes, doesnot have to depend on a linear correlation with the thickness of thelayer.

In order, that in the use of a round magnetron source having thesubstrate movement as described, static components are inserted to reachan acceptable coating thickness apportionment, presently, between themotion path of the substrate and the sputter surface, which establishthe apportionment of the material flow between the sputter surface andthe substrate, these components are known as aperture orifices or“Shaper Orifices”. Normally, in this case, the said aperture orificesare combined with the circular disk shaped sputter surfaces, and, as hasbeen mentioned, the magnetic field pattern cyclically moves along thesputter surface by rotation about an axis vertically extending from thesputter surface.

The provision of components of this type, such as the said shaperorifices, does well to enable the achievement of layer thicknessapportionments on the mobile substrate with deviations from the averageof the layer thicknesses of less then 1%, but only when one takes intoconsideration, the essential disadvantage, that by means of suchinterposed components considerable quantities of sputtered material aremasked out before they reach the substrate, wherewith, at a uniformsputter rate the coating rate is essentially reduced.

These components, which often must be matched to the currently employedsputter sources, and upon each modification, especially the magnetronmagnetic field pattern and its motion must be set up anew and optimizedwith the aid of iterated steps, while the coating process itselfproduces a disturbed layering. Because of the considerable heating ofsuch components in the process space, layer tensions can arise, which,for example, together with thermally conditioned shaping changes, suchas the distortion of such components, lead to a situation, in which thementioned disturbed layer can exfoliate and deposits on the substratecan lead to coating defects.

SUMMARY OF THE INVENTION

Thus it is the purpose of the present invention, to propose a procedurefor the production of magnetron sputter coated substrate of the kinddescribed in the opening passages, as well as proposing equipmentdesigned for the said procedure, to achieve the result, that substratewith essentially improved apportionment of sputtered off material isdeposited along the sputter coated surface with essentially reducedmaterial flow masking as compared to the heretofore attainableapportionment with the described reduced masking.

This will be achieved with a production procedure of the type mentionedin the introductory passages of this description, in that, in accordwith the wording of the characterizations of claim 1, the quantity ofmaterial deposited per time unit on the substrate is cyclically changedin conformity with the phase locking of the cyclical motion of themagnetic field pattern.

So that the present invention can be immediately understood at thisplace, its principle, as set forth in FIG. 1 will be explained.

In FIG. 1, the cross-hatched circle S depicts a position of a magnetronsputter source on a sputter surface, at which position the maximumsputter rate is generated. A position S of this nature represents,accordingly, a section of the area of the magnetron magnetic fieldpattern. Since, in the case of FIG. 1, the existing and here concernedphenomena known to the invention are outlined schematically, only thisposition S should be taken as representative of the increased sputterrate in the area of the magnetron magnetic field pattern. By means ofthe two dimensional cyclic motion shown here, namely, a cyclic movementy_(z), and, at right angles thereto, a cyclic motion x_(z) would producean elliptic movement path, along which the position S moves itself abovethe sputter surface.

Above and along the sputter surface with the two dimensional, cyclicmovable position S, runs a substrate SU with a uniform speed v. If oneassumes, that the position S at a specific period proceeds from oneposition, pos. m to the next position, pos. m+1—as is shown in FIG.1—within equal times, then there is built upon the substrate SU, thoselayers, the location of which are marked with a cross X. It isimmediately obvious, that upon the substrate SU, a cycloid path is beingfollowed.

Examination also shows, that the position S dwells for a longer periodin the flex points about X_(W) than in the zero-transient points X_(N).This has the result that in the edged or peripheral areas of thesubstrate SU, a larger quantity of material of the released material isdeposited than in the central sections.

If one now makes use of the present invention on the base of thetheoretically presented relationships as shown in FIG. 1, and changes,by means of the cyclic and phase locked per-time-unit relationship, thequantity of material deposited on the substrate in such a manner, thatthe said quantity is always diminished, when the position S lies on theareas X_(W), and the said quantity is always increased, when theposition S crosses over the areas X_(N), then the achievement is, thatthe said inhomogeneous apportionment of the coating materials laid downupon the substrate SU in the y-direction is adjusted into a homogeneousand desired apportionment.

In an advantageous embodiment of the invented production method, thecyclic motion of the magnetron magnetic field pattern is made twodimensional, preferably realized by means of a pendular or a circularrotational movement about an axis perpendicular to the sputter surface,which has the end result of curving in Lissajous figures.

Further, the cyclic motion of the magnetic field pattern need not be inany case necessarily two-dimensional. If, for example, where alongitudinally extended target is involved, the magnetic field patternis only cyclically moved in the said longitudinal extension of thesputter surface on the longitudinal target and the substrate isdisplaced perpendicularly to this movement. In this case, the saidinhomogeneosities of the deposition thicknesses on the substrate in thedirection of the target longitudinal extension, in accord with theinvention, can be compensated for by a cyclic change of the sputter ratealong with phase lock of the cyclical motion of the magnetic fieldpattern.

It is quite possible, to bring about the cyclic change of the materialquantity laid down on the substrate along the sputter surface in alocalized manner. In a considerably more favorable embodiment, theproposal is made, that changes in the deposited quantity of material canbe phase locked simultaneously in common with the cyclic motion of themagnetic field pattern over the entire sputter surface.

DEFINITION

We understand in regard to two mutually phase locked cyclic signals, twoperiodic signals, which, respectively, in accord with a fixed number ofperiods of one of the signals, are again in the predetermined phaserelationship with one another. Seen within a given window of time, theirfrequencies f₁ and f₂ differ from one another by a factor correspondingto a rational number.

In a most advantageous manner, over the entire sputter surface adeposited quantity of material can be simultaneously changed, in thatthe sputter-power is changed.

Instead of, or rather in addition to, the change of the depositedquantity of material by means of a change of the sputter power, it ispossible that the said quantity of material, localized or even over theentire sputter surface can be changed, by an alteration in the reactivegas flow and/or by adjusting the operational gas flow, such as, forexample, a flow of argon in the process space.

Beyond this, it is possible, and preferable, to have the sputter surfaceconsist uniformly of a single material for sputtering, such as of onemetal, a metal alloy or a metal composite. It is, however, furtherpossible, by the use of a multicomponent target, to have surfacesections of materials of differing sputtering characteristics.

If one again observes FIG. 1, again theoretically, it can be recognizedthat the deposited quantity of material should then possess a minimum,when the position S takes up a location X_(W) on the substrate SU. Inthis respect, it is understandable, that in a further approvedembodiment, the phase locked, cyclical change of the material quantitycan be realized by a curve in respect to the time, the frequencyspectrum of which has a dominant spectral line at the said doublefrequency in regard to the frequency of the cyclic magnetic fieldpattern movement.

In an additional advantageous embodiment, it is also proposed, that, thementioned curve possesses a further dominant spectral line upon thefrequency of the cyclic magnetic field pattern motion. This becomesparticularly evident, when not, as is shown in FIG. 1, the substrate SUmoves linearly above the sputter surface, seen in FIG. 1 as a top viewof the sputter surface, but, in just such a top view, here drawn incross-hatching, the substrate SU moves preferably in a curved track,that is, a circular path with a center of curvature outside of thesputter surface.

In regard to the proposal cited immediately above, fundamentally, wherea two dimensional, cyclic motion of the cyclic magnetic field pattern isconcerned, that particular movement component is decisive, which isperpendicular to the movement direction of the substrate, still seen asin top view against the sputter surface. The cyclic movements of themagnetic field differentiate themselves in FIG. 1 in the y- and thex-axis. If the movement of the substrate is carried out with a componentin the x-direction, then, correspondingly what is decisive, is that thecyclic magnetic field pattern motion must be in the y-direction forphase locking with the cyclic change of the sputter rate.

In another advantageous embodiment of the present invention, themagnetic field pattern is designed to be mirror-symmetric to an axis inone plane, which plane is parallel to the sputter surface, or mirrorsymmetric to two, mutually perpendicular such axes.

In an additional preferred embodiment, namely, for reactive magneticsputter coatings, a reactive gas is provided in the process spacebetween the sputter surface and substrate.

Although by no means compulsory, advantageously, additionally a circularsputter surface can be employed, with simplifies the complete assemblyof the magnetron source.

In a further approved embodiment of the present invention, between thesputter surface and the substrate none of the material-flow disturbingcomponents exists in relation to the aforementioned aperture orifice.

Advantageously, the curve of the phase locked, cyclic change of thematerial quantity deposited on the substrate is selected dependent uponthe relative motion between the substrate and the sputter surfacesand/or dependent upon the shape of the magnetic field pattern and/ordependent upon the cyclic magnetic field pattern movement.

During the operational life of the source targets, which define thesputter surface, the geometry of the sputter surface undergoes change,because of the erosion of sputter. This, in turn, gives rise, duringsaid operational life of the target, to a changing apportionment withina cycle of the magnetic field pattern motion of the off-sputteredmaterials from the sputter surface and therewith a changing of theapportionment of the quantity of material carried to the substratesurface. Such a change of the sputter characteristics at the sourceitself cannot be corrected by means of provided static components suchas the said aperture orifices. Conversely, the present invention opensthe possibility, to take up just such phenomena regarding theapportionment of specified substrate layer thicknesses, since, in accordwith a further advantageous embodiment of the invention, the procedureof the phase locked, cyclic change is subjected to a time-change. Withsuch a time based alteration of the procedure of the phase lockedcyclical change, for example, the amplitude or the curve shape thereof,can be thoroughly controlled and executed in accord with empiricallybased values by means of a given process. In another advantageousembodiment, this is done in that one measures the material apportionmentas it has been immediately deposited on the substrate as a “rulequantity”. This said rule quantity is then compared with a standardapportionment and then, in accord with the direction of the comparisonresults, namely a “rule difference”, the procedure of the phase locked,cyclic change is presented as a standard value, in a control circuit forthe quantity of material distribution. In this way, it becomes possibleto automatically undertake a resulting shift in material apportionment.In a completely different, but favorable, embodiment of the invention,the substrate can be moved over the sputter surface a plurality oftimes. This is done advantageously, in that the substrate is guidedcyclically over the sputter surface, which can be in a regulated to andfro movement.

In a preferred manner, the substrate is linearly moved parallel to theoppositely situated sputter surface. When this occurs, it can be moved,in a first additional, advantageous way, in a plane parallel to thesputter surface or in a second favorable manner, in which the substrateis moved, again situated opposite to the sputter surface, not linearlyas before, but rather in an advantageously circular path.

If the substrate, planarly situated parallel to the opposing sputtersurface is linearly moved, then, favorably, and as explained above, ineach case the phase locked, cyclic alteration of the quantity ofmaterial is carried out in a procedural run, the frequency spectrum ofwhich evidences a dominant spectral line in a case of a doubledfrequency in relation to the frequency of the cyclic magnetic fieldpattern motion. This takes place, in both cases, first, if the substrateis moved in a plane parallel to the sputter surface, and second, if thesubstrate, aligned planarly parallel to the sputter surface, is movednon-linearly, that is along the said circular path.

If now, the substrate, again planarly parallel to the sputter surface,is moved non-linearly, preferably along the said circular path, then itcan be demonstrated, that additionally to the said quantity of materialdeposited on the substrate by means of the cyclic motion of the magneticfield pattern phase locked variation, then the said quantity of materialcan be changed synchronously with the movement of the substrate, as thisis amply explained in WO 00/71774.

If the substrate motion is carried out, in a nonlinear manner, againplanarly parallel opposed to the sputter surface, in this casepreferably along a circular path with the radius of curvature beingoutside of the sputter surface, then the course of the cyclic variationof the quantity of material, over a time period, is formed with adominant frequency component both in a case of the double as well as anequal frequency, in relation to the frequency of the cyclic pattermotion. Although, in addition, in accord with the present invention, thepossibility exists of achieving the striven for, desired layer thicknessapportionment profile on the substrate, it is also possible in a highlypreferred manner to realized on the substrates an optimized, homogenouslayer thickness apportionment. In this way, again advantageously,planar, magnetron sputter coated substrates are produced.

A magnetron sputter coating apparatus in accord with the presentinvention consists of a magnetron source and a cyclically driven magnetarrangement underneath a sputter target, situated in a plane parallel tothe sputter surface, and consists further of a substrate transportapparatus, by means of which a substrate is moved above the sputtersurface. This so defined magnetron coating apparatus then has amodulation arrangement for the per-time-unit of sputtered quantity ofmaterial from the said source, and this quantity is modulated cyclicallyand with phase locked with the cyclic motion of the said magnetarrangement.

Advantageous embodiments of the magnetron sputter coating apparatus inaccord with the present invention are specified in the claim.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now explained, for example, with the aid of Figures.These show in:

FIG. 1, schematically presented, and without claim on physicalexactness, the distinguishing relationships, which serve as a basis forthe present invention of a magnetron sputter source with a mobilemagnetron magnetic field pattern and moveable substrate,

FIG. 2, schematically and simplified, a first embodiment of the inventedmethod, that is to say, an invented apparatus,

FIG. 3, in a presentation analogous to that of FIG. 2, a preferredembodiment, as of the present day, of the invented method, that is tosay, of an invented apparatus,

FIG. 4, a plan view, of an advantageously employed rounded magnetronsource within the bounds of the invention, with various paths of motioncorresponding to the present invention, of a substrate as a basis for aconsideration of the path-specific optimized design of the presentinvention,

FIG. 5, the source, in accord with FIG. 4, schematically presentedcross-section,

FIG. 6, schematically, and highly simplified, an inline magnetronsputter coating apparatus, whereby the substrate, mobile in relation tothe said source is realized, the said mobile substrate being aspresented in FIG. 4,

FIG. 7, once again schematically and highly simplified, an apparatus,wherein substrates traveling on a circular path are moved past thesource in accord with second movement-method presented in FIG. 4,

FIG. 8 and FIG. 9,

layer thickness apportionments on the substrate, accruing depositedmaterial in relation to their direction of motion, without anycompensation,

(a) with, as in the known manner, a provided aperture orifice,

(b and c) realized with the present invention, and in

FIG. 10, an additional type of the relative motion between substrate andthe source.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2, simplified and schematic, is shown a first embodiment of aninvented magnetron sputter coating apparatus, i.e., a first variant ofthe method of production in accord with the present invention.

A target 1, advantageously of one piece and of a material M or, one ortwo pieces (note dotted lines) from respectively the materials M₁, M₂, .. . A magnetron sputter source, not presented in details, is fed bymeans of an electrical generator arrangement 3 in reference to a (notshown) anode of the said source. This feed is normally DC, if necessaryboth with DC and AC or only with AC, with the current in the highfrequency area R_(f). Thereby, the schematically drawn in electricalfield E, which was presented in FIG. 1, is shown in the known means andway. Beneath the target 1 is provided a magnet arrangement 5, themagnetic field of which penetrates through the target 1 with field lineswhich protrude from and reenter into the sputter surface 7. The fieldlines H form a field pattern 9 in the shape of a closed, tunnel-likeloop. The magnetron magnetic field pattern, in a known manner, leadscommonly with the electrical field leads to a marked plasma densityincrease in the area of the magnetic field pattern 9 with a therewithresulting increase of the sputter rate. The magnet arrangement 5generates in most cases, as already mentioned, the magnetic fieldpattern 9 on the sputter surface 7, which field then appears as closedloops.

As FIG. 1 shows further, with (not depicted here) driving means, themagnet arrangement 5 moves along the target 1 in a back and forthmanner, in at least in the y-direction in accord with FIG. 1, this beinga cyclic movement, as is indicated by the double arrow M_(y). With themagnet arrangement 5 being underneath the target 1, the magnetic fieldpattern 9 moves uniformly along the sputter surface 7.

Distanced from the sputter surface 7, a substrate 11 is moved past saidsputter surface, doing this with at least a motion component m_(x),which is perpendicular to the magnetic arrangement 5 and therebyperpendicular to the magnetic field pattern 9. In accord with thefundamental principle of the present invention, the rate of thematerials sputtered from the said sputter surface 7 changes cyclicallyin accord with phase locking with the cyclic movement M_(y) of themagnet arrangement 5. In other words, the magnetic field pattern 9 ismodulated. These said changes can be realized with the embodiment ofFIG. 1, in that between the magnetic arrangement 5 and the sputtersurface 7 in the motion direction M_(y) of the magnet arrangement 5, themagnetic resistance of the penetrating power (punch-through) between themagnet arrangement 5 and the sputter surface 7 locally varies or islocally modulated. As is schematically depicted in FIG. 1, it ispossible to bring these changes about by adding locally increasingmaterial inserts 13 to the magnetic resistance of the target 1, whereby,along the sputter surface 7, the field strength H of the magnetic fieldpattern 9 will be locally modulated, as will the thereto associatedsputter rate. This opens for the expert additional possibilities ofmodulating the sputter rate locally and in phase locking with cyclicmotion of the magnetic arrangement 5. Among these possibilities wouldbe, modulating the sputter rate:

-   -   by provision of electro magnets on the magnet arrangement 5,    -   by mechanical displacement of individual magnets of the said        magnet arrangement 5,    -   by modulation of the separating distance between the magnet        arrangement 5 and target 1, and the like.

Fundamentally, in the case of a procedure based on FIG. 1, the sputterrate along the sputter surface 7 is thus locally modulated.

In FIG. 3 is a presentation, showing, analogously to FIG. 2, anadditional fundamental embodiment of the present invention, whichembodiment, at least now, can be clearly set forth. Having at hand theprocedures and components of FIG. 2, the same are depicted again in FIG.3 using the same reference numbers, and need not be described onceagain. As is illustrated in FIG. 3, the movement M_(y) of the magnetarrangement 5 is effected by a drive 15. The electrical generatorassembly 3 for the target 1 has a control entry (or a modulation entry)S₃. An operational default 17 of the method, the output A₁₇ of which, isin active connection with the control entry S₃, produces a cyclic,periodic modulation signal for the generator assembly 3 with aspecified, preselected course of operational running. If one designatesthe cyclic frequency of the motion M_(y) of the magnetic arrangement 5and therewith, that of the magnetic field pattern 9 with f₁, then thefrequency f₂ of the periodic control signal, which is produced at theunit 17, is being selected as n·f₁, where n is a rational number. Theperiodic control signal of frequency f₂, which is conducted to thecontrol input entry S₃, is phase locked with the cyclic movement M_(y)of the magnet arrangement 5 with the frequency f₁. This means that thephase position of the control signal, in reference to the cyclicmovement m_(y), is respectively equal to a given number n of periods ofthe cyclic control signal. In this respect, there exists an entry of thedefault unit 17 accommodating the mechanical outlet A₁₇ of the drive 15or, and preferentially, an active connection with the electrical entryE₁₅ of the drive 15, as is schematically illustrated, this being doneadvantageously by means of an adjustable phase presetting unit 18. Atthe unit 17 are provided, advantageously, additional inlets S₁₇, ontowhich values of the cyclic control signal curve, especially frequencyf₂, can be adjusted as to a curve shape with the amplitude and the like.

As shown in FIG. 3, again presented schematically and in dotted lines,it is possible, changes can be made, so that instead of, or in additionto, the advantageous variation of the sputter capacity, by means of thegenerator assembly 3, phase locked by means of phase preset unit 18, areactive gas G_(r) and/or a working gas G_(A) such as argon can be fedinto the reaction space between the sputter surface 7 and the substrate11. The change can, in this respect, be made on a wide spread basis overthe entire sputter surface 7, or locally along predetermined areas ofthe said sputter surface 7.

Differing from the embodiment in accord with FIG. 2, in the case of theembodiment following that of FIG. 3, which is preferred today, thesputter rate on the sputter surface 7, which is phase locked with thecyclic motion of the magnet arrangement 5, is not locally changed, butrather the entire existing sputter rate at the sputter surface 7, phaselocked with the magnet arrangement motion M_(y), is changed.

In FIG. 4, schematically shown, and in top view, is a round-magnetronsputter source 21, which is both in keeping with the present inventionand can be advantageously employed. Illustrated is the target 23thereof, i.e., the sputter surface of the magnetic field pattern 9′ andthis is drawn in dotted lines thereon. The magnet arrangement 25 isdesigned in the here presented top view, mirror image symmetrically toan axis which is situated parallel to the said sputter surface of thetarget 23 and the said arrangement is cardioid is shape. The referencenumber 27 designates schematically the substrate which is movable, inaccord with the invention, in the x-direction. The cyclic movement ofthe magnet arrangement, as located in FIGS. 2, 3 is, in this case, herein an advantageous manner, realized as a two dimensional cyclicmovement, with the movement components M_(y) and M_(x) running at thesame frequency. This cyclic, two dimensional motion is advantageously,and also as presented in FIG. 4, effected by a rotation of the magnetarrangement 25 about the axis 24.

Obviously, it is possible, if required, instead of a circular rotation,to employ a rotating pendulous motion. In addition, instead of thepresented single axle mirror symmetrical magnet arrangement 25, anotherform of the magnet arrangement can be used. Especially is it possible,as has already been mention in the introductory passages to consider adouble axis, mirror symmetrical magnet arrangement, for instance in theform of the numeral “8” with a central rotation axis 24, for example,this being the center of possibly also a kidney shaped unit.

In FIG. 5, the round magnetron sputter source, as per FIG. 4, isschematically shown in cross-section, wherein the reference number 29designates the mounting location of a conventional aperture orifice,this being indicated by dotted lines. In regard to this, it should beemphasized, that in accord with the present invention, only under thegreatest considerations, would be the installation of a designedaperture, which would allow masking of the sputtered off materials fromthe sputter surface to be essentially much less than the conventionallyinstalled apertures. In other words, in accord with the presentinvention, the required layer deposit thicknesses can be attainedentirely without the provision of such components.

Advantageously, the substrate 27 can be passed by the source 21 manytimes, if this is in a direction which remains unchanged, or if this isa back and forth motion.

As has already been mentioned, the modulation curve form, which is usedin accord with the invention, modulates the sputter rate. The saidsputter rate is phase locked with the magnet arrangement-cyclic motion.The sputter rate is that deposited quantity of material during any giventime period and is dependent upon the shape of the magnet arrangementand its motion dynamics, and further dependent upon the moving path anddynamic of the substrate motion. For example, there is presented in thefollowing, three cases which will be examined. The first and secondcases are found in the FIGS. 4, 5 wherein the substrate 27 is moved in aplane parallel to the sputter surface of the target 23. The saidmovement is linear in respect to the dotted path A-B or non linear inaccord with the alternate path A-B′, thereby advantageously on acircular path about a (not shown) center Z which lies outside of thesputter surface of the target 23. The third case comprises a movement ofthe substrate 27 upon a linear path, such as A-B is, as a rule, given inthe case of so-called inline-coating equipment. Such an in-line coatingequipment example is shown in FIG. 6. The substrate lies, in this case,on a substrate carrier and would be, as though it were on a runningbelt, passed one or more times, preferably the latter, linearly beneaththe sputter source. In the case of the previous procedure, a providedaperture orifice would have been installed at location 29, if theinstallation were not in accord with the present invention.

FIG. 7, schematically, shows how the non-linear motion path A-B′, as perFIG. 4, for example, is carried out. In this case, the substrate 27 ison a disk shaped or a domed substrate carrier 30′, with a center ofrotation z outside of the sputter surface of the source 21. In FIG. 7,the reference number 29″ provides the location, where, in accord withup-to-now technology, an aperture orifice must be installed.

In accord with FIG. 4, the substrate 27 possesses a range with anextension in the y-direction from y₁ to y₂, which, with specified layerthickness apportionment, should be, as much as possible, coated with ahomogeneous layer. In accord with the present invention, with amodulation of the sputter capacity, the sputter rate for each positionof the rotating magnet arrangement 25 is directly influenced, in orderthat, by an appropriate selection of the modulation curve, ahomogenization of the resulting layer thickness on the substrate can beattained, without the installation of an aperture orifice or, at themost, with the installation of an aperture orifice with essentially lesssputter masking properties than would be the case with conventionalapertures.

As has already been made plain in FIG. 1, confirmation has been made,that in the case of the linear movement A-B, or for that matter, whereany linear motion component is concerned, it is of advantage to selectthe basic modulation frequency in accord with f₂ of FIG. 3 at thedoubled rotational frequency f₁ of the magnet arrangement 25, 5 undersuch circumstances, that no additional asymmetries need be corrected. Inthis way, a modulation curve form is advantageously chosen at thedefault unit 17 (FIG. 3), which has in its frequency spectrum at 2f₁ ata transcending spectral amplitude. The rotation frequency, i.e. thecyclic frequency in accord with f₁ of the magnet arrangement 25, 5 mustbe set so high, that during the movement of the substrate 27, 11 as itpasses the source, the magnet arrangement 25, 5 runs through a pluralityof cycles, which is assured by a corresponding increase of the magnetarrangement cyclic frequency, i.e., a slowing of the substrate velocity.Typical cyclic frequencies of the movement M_(y), again as shown in FIG.3, or in other words, the rotation in accord with FIG. 4, lie in that Hzrange generally between 0.1 and 10 Hz and the movement of the substrate27, 5, as it passes the sputter source endures for several seconds, evenwhen the substrate is passed by the magnetron sputter source only once.In the case of a multipassage of the substrate past the sputter surface,the substrate motion can be increased in its speed. In any case, caremust be taken here, in that the cycle, at which the substrate passes thesputter surface, is made asynchronous to the cycle of the magnetarrangement motion. In the case of a cycle of the substrate movement insynchrony with that of magnet arrangement, it becomes necessary, in someinstances, that additional manipulation of the sputter rate be employed,which said rate is synchronized with the substrate movement.

FIG. 8 presents the simulated curve of the coating layer thicknessapportionment on a plane substrate, which, in accord with FIG. 4, hasbeen moved over the sputter surface a plurality of times along motionpath A-B. In this drawing, D designates the diameter of the circularsputter surface, and the positions y₁ and y₂ show the correspondinglocations on the substrate 27 of FIG. 4. The y-direction corresponds tothe y-direction on the substrate, in accord with FIG. 4, that is to say,the y-direction in accord with the FIGS. 2, 3. Curve (a) shows the layerthickness, if the sputter coating apparatus is used without the inventedsputter-rate modulation and without use of the aperture orifice. Thecurve (b) exhibits, again without use of the invented sputter-ratemodulation, but with the provision of an aperture orifice 29′, as thisis shown in FIG. 8. The curve (c) designates the result in the case ofthe invented employment of the cyclic variation, i.e., modulation, ofthe sputter rate, in accord with the phase locked cyclic movement of themagnet arrangement, as this is also brought about as per FIGS. 3, 4. Amodulation curve was used, the spectrum of which has basically aspecifically harmonic, superimposed spectral line. The simulated curvesin accord with FIG. 8 have essentially proven themselves in the meantimein practice. By the omission of the aperture orifice 29′ and the use ofmeasures in accord with the present invention, essentially, all of thematerial set free from the sputter surface reaches the substrate, whichleads to a significantly increased coating rate, along with shortercoating times and greater productivity. According to FIG. 8, the coatingrate is increased, about some 18%. This is accomplished during auniform, average electrical consumption at the magnetron source andbeyond this, especially with a method in accord with FIG. 4, showingefficient use of target material, all leading to better operational lifeof the coating equipment. By the use of an aperture orifice, it ispossible, that the loss relative to the coating rate cannot be simplycompensated by an increase of the applied electrical load, because themaximum usable electric sputter load at the target is generally limitedby the efficiency of the provided target cooling.

In a case of a reactive magnetron sputter coating apparatus process,wherein (not shown) in all executable forms of the present invention,between the magnetron sputter source and the substrate, a reactive gasis released, there arises accordingly, deficiencies in the layer qualitydue to excessive source loading. Because of such excessive loading, thereaction process of the material set free changes with the reactive gas,which in turn leads to stoichiometric changes of the deposited material.In this case, it is possible, for example, that the optical absorptionin one or more layers, because of the said changed stoichiometry, isincreased in a disturbing amount.

The second of the above mentioned three substrate movement types is asshown in FIG. 4, i.e., non-linear, and specially along a circular pathAB′. The path of movement of the substrate, possesses in this situation,as is obvious, both a movement component M.sub.x, that is in thedirection of A-B as well as a movement component perpendicular thereto,namely M_(y). An asymmetric layer thickness apportionment arisestherefrom, in relation to the y-extension of the substrate. This is madeclear by an observation of FIG. 7. In the y-direction, displacedsubstrate areas are moved with different velocities over areas ofdifferent lengths on the sputter surface in relation to the magnetronsputter sources extending along axis z. The corresponding resultsevolved in FIG. 8 for this case are presented in FIG. 9. The curve ofthe layer thickness upon the coating with one arrangement, as this isshown in FIGS. 4, 2, without the use of the invented sputter ratemodulation and without the use of an aperture orifice is shown in (a).In order to compensate for the strongly inhomogeneous apportionment (a)with an aperture orifice 29″, it is necessary that the latter beappropriately asymmetrically shaped. The curve of the coating with theprovided aperture orifice 29″, but without the use of the inventedsputter rate modulation, is indicated by the curve (b). The curve (c)shows the layer thickness apportionment with the use of the inventedsputter rate modulation. In this situation, analogous observationsregarding FIG. 8, a modulated, cyclic curve was chosen, which, first,because of the substrate motion in the x-direction corresponding toM_(x) of FIG. 4, with the doubled frequency of the cyclic magneticarrangement movement, its frequency spectrum exhibits a predominatespectral amplitude. Second, however, in order to consider the ratedifferences due to the different movement radii of the differentsubstrate units in the y-direction in accord with discussion of FIG. 7,a further predominate spectral amplitude can be attained, wherein thefrequency equals the frequency of the cyclic magnet arrangement motion.

Employed is a simple, mirror symmetric magnet arrangement with an offsetaxis of rotation in accord with FIG. 4, since, in the case of adouble-axis symmetrical magnet arrangement, for example in the form of afigure “8” with a sputter rate modulation with predominate modulationfrequency, which corresponds to that of the magnet arrangement motion,no asymmetry in the sputter rate and the therewith associated coatingrate can be achieved. If a simple mirror symmetric magnet system inaccord with FIG. 4 is employed, then it becomes possible to reach thenecessary asymmetry with the design of this magnet system, which carriesout the remaining homogenizing of the layer thickness apportionment inthe manner of FIG. 8, that is to say, with linear movement components inthe direction of A-B in accord with FIG. 4, with the aid of the sputterrate modulation, holding to the doubled frequency, based on thefrequency of the cyclic magnet arrangement motion.

Both in the case of a linear substrate path parallel to the sputtersurface, as well as in the case of a curved substrate path, againparallel to the substrate surface it is possible, as has been described,with the aid of the sputter rate modulation, especially realized bymeans of sputter capacity modulation in accord with FIG. 3, to achieve avery good layer thickness apportionment, without the necessity, thataperture orifices must be installed. Thereby, an optimization of thelayer thickness apportionment is enabled by means of an externalvariable process parameter, namely the electrical sputter loading.Essentially for the optimal functioning of the invented dynamic layerthickness apportionment correction measures, the speed, that is, therate of change, with which the electrical load, which is conducted tothe source, can be altered. With the present day, commerciallyobtainable power-supplies, an additional possibility is, to modulate theoutput loading in the small signal type, that is, typically plus orminus 1 to 10% about the static operational point loading, withfrequencies up to the range of above 100 Hz without significant signalinrush. In this way, even complex modulation curve shapes with basicfrequencies in the range of more than 10 Hz and significant highspectral portions can be made with considerable exactness and withoutessential phase slipping. This is important for a precise running of themodulation and the phase locking with the cyclic magnet arrangementmotion.

The greater coating rate, i.e. sputter rate, can also, in accord withthe invention, be attained in a case of a reactive magnetron sputterprocess. The relevant time-constant, (which lies in a range exceedingca. 100 msec) for the stability of the reactive process is dependentupon the process, for example, dependent upon the relative gas pressure,sputter rate, chamber geometry, vacuum pump characteristics and thelike. In the case of a cycle frequency, that is, the rotationalfrequency, of the magnet arrangement 25, 5, as seen in FIGS. 4, 3, of afew Hz, the relevant time-constant τ=1/(2 τ f) for the changing of thecoating rate, for example, the sputter rate lies definitely under thiscited 100 msec, whereby the influencing of the reactive process is onlyminimal. In other words, the reactive process is normally too sluggish,than that it can be particularly disturbed by the invented, activelyused, sputter rate modulation.

FIG. 10 shows, schematically, the third case of the substrate motion, inaccord with which, possibly additional to the formulation of themovement path, as presented in FIG. 4, the movement path, seen in adirection parallel to the sputter surface of the source 21, is curved,advantageously in accord with a circular arc. In this case, besides thealready explained sputter rate, modulation course, which relates to thepath A-B or A-B′, this phase locked with the cyclic motion of the magnetarrangement—as this is explained in WO 00/71774 is—the sputter ratechanges with an additional modulation, now, however, synchronized withthe substrate movement, in order to even out the stringy effectmentioned in the introductory passages.

The optimization of the layer thickness apportionment in accord with thepresent invention, and especially by means of the externally availableprocess parameter “sputter loading” enables also a matching to theactual erosion condition of the target in the concept of a placement ofthe modulation curve shape onto currently appearing relationships. Inthis way, it is possible that the remainder dependency of the layerthickness apportionment by means of the operational life of the targetcan easily be eliminated. Because the influencing of the apportionmentby means of the changing, that is to say, because of the modulation ofthe sputter rate, especially in a case wherein modulation of the sputterloading is done practically without delay and enables a partitioning byin-situ-control. In this way, with the aid of an appropriate in-situmeasurement system the presently effective layer thickness apportionmentat the moment is done, for example, through the so called broad-bandspectral monitoring and the measurement result can be used as acontrol-value in a regulation circuit for the control of the layerthickness apportionment.

This is presented schematically and in dotted lines in FIG. 3. By meansof the measurement system 40 for layer thickness in-situ, theinstantaneous layer thickness apportionment on the substrate 11 isdetermined. At a comparator unit 42, the measured apportionment iscompared with an existing memory statement 44 of a specifiedapportionment, which was input in the form of, so to speak, a table. Theoutput of the comparator 42, with the control difference Δ, is activelybound at the control input S₁₇ of the modulation default unit 17, and atthis location, the course of the sputter rate modulation in the functionof the control difference Δ which appears at the output of thecomparator 42 is held up to such a time, until the measured layerthickness apportionment no longer deviates from the specifiedapportionment W, as this difference is given within the allowableremaining control deviation.

Even if greatly emphasized in the course of the description of thepresent invention, attention is directed to the achieving of anoptimized, homogeneous layer thickness apportionment on the producedsubstrates. It is, without further consideration, obvious, that by meansof an appropriate design of the sputter rate modulation, determinationmay be made as to what kind of a basic frequency, curve characteristic,and phase situation should be properly associated with the movementcycle of the magnet arrangement. Other desirable layer thicknessapportionments on the substrate can be attained, when seen in adirection transverse to the motion direction of the substrate whichsubstrate is in the form of a plane and is parallel to the sputtersurface.

1. A method for manufacturing a coated substrate by magnetron sputteringcomprising: a) providing a magnetron source with a sputter surface, themagnetron source generating a magnetron magnetic field pattern along thesputter surface; b) cyclically moving said magnetron magnetic fieldpattern along said sputter surface; c) positioning a substrate to becoated a distance from and facing said sputter surface; d) moving saidsubstrate along said sputter surface; and e) varying an amount ofmaterial deposited on said total substrate per time unit from saidmagnetron source that is cyclically and phase-locked with saidcyclically moving said magnetron magnetic field pattern.
 2. The methodof claim 1, further comprising cyclically moving said magnetron magneticfield pattern in two dimensions.
 3. The method of claim 1, furthercomprising cyclically moving said magnetron magnetic field in at leastone of a rotational pendular manner and a rotational manner with respectto an axis perpendicular to said sputter surface.
 4. The method of claim1, further comprising cyclically varying said amount of materialsimultaneously along the entire sputter surface.
 5. The method of claim1, further comprising varying said amount of material by varying atleast one of a flow of a reactive gas and a flow of a working gas intoan area between said sputter surface and said substrate.
 6. The methodof claim 1, further comprising varying said amount of material bycontrolling a power applied to said magnetron source.
 7. The method ofclaim 1, further comprising varying said amount of material with a timecourse having a frequency spectrum with a significant spectral line at adouble frequency of a fundamental frequency of cyclically moving saidmagnetron magnetic field pattern.
 8. The method of claim 7, wherein saidtime course has a further significant spectral line at the fundamentalfrequency of cyclically moving said magnetron magnetic field pattern. 9.The method of claim 1, further comprising tailoring said magnetronmagnetic field pattern symmetrically to an axis in a plane which isparallel to said sputter surface.
 10. The method of claim 1, furthercomprising tailoring said magnetron magnetic field pattern symmetricallywith respect to two mutually perpendicular axes in a plane which isparallel to said sputter surface.
 11. The method of claim 1, furthercomprising applying a reactive gas into an area between said sputtersurface and said substrate.
 12. The method of claim 1, wherein saidsputter surface comprises a circular surface.
 13. The method of claim 1,further comprising not influencing a material flow distribution fromsaid sputter surface to said substrate.
 14. The method of claim 1,further comprising selecting a time course of varying said amount ofmaterial with respect to at least one of a relative movement between thesubstrate and the sputter surface, a shape ofsaid magnetron magneticfield pattern, and a movement course of said magnetron magnetic fieldpattern.
 15. The method of claim 1, further comprising time varying acourse of varying said amount of material.
 16. The method of claim 1,further comprising monitoring a distribution of material momentarilydeposited on said substrate, comparing said monitored distribution witha desired distribution, and adjusting characteristics of varying saidamount of material as a function of a difference between said desireddistribution and said monitored distribution in a negative feedbackcontrol loop.
 17. The method of claim 1, further comprising repeatedlymoving said substrate along said sputter surface.
 18. The method ofclaim 1, further comprising cyclically moving said substrate along saidsputter surface in at least one of a single direction motion and a forthand back motion.
 19. The method of claim 1, further comprising movingsaid substrate along said sputter surface linearly as considered in aview towards said sputter surface.
 20. The method of claim 1, furthercomprising moving said substrate within a plane parallel to said sputtersurface.
 21. The method of claim 1, further comprising moving saidsubstrate along a non-linear trajectory path as considered in a viewparallel to said sputter surface.
 22. The method of claim 1, furthercomprising moving said substrate along a non-linear path as consideredin a view onto said sputter surface.
 23. The method of claim 1, furthercomprising moving said substrate along a circular trajectory path asconsidered in a view towards said sputter surface about a center remotefrom said sputter surface.
 24. The method of claim 1, further comprisingsuperposing to said varying of said amount of material a further varyingof said amount synchronized with said moving of said substrate.
 25. Themethod of claim 1, wherein an optimized homogeneous coating thicknessdistribution is achieved on said substrate.
 26. The method of claim 1,wherein an optimized homogeneous distribution of material stoichiometryis achieved along the coating of said substrate.
 27. The method of claim1, wherein the method of magnetron sputtering comprises a method ofcoating planar substrates.
 28. The method of claim 1, wherein saidcoated substrate has a coating thickness deviation from an averagecoating thickness value which is less than or equal to 1% consideredalong a substrate surface that is greater than 1,000 cm².
 29. The methodof claim 1, wherein said coated substrate has a local deviation ofdeposited amount of material of at most 0.01% with respect to an averagevalue along a substrate surface of at least 10 cm².
 30. A magnetronsputtering apparatus comprising a) a magnetron sputter source having asputter target with a sputter surface and a magnet arrangement, saidmagnet arrangement being coupled to a drive to be cyclically moved alonga plane parallel to said sputter surface; b) a substrate conveyorarrangement for moving at least one substrate along said sputtersurface; and c) a modulation arrangement cyclically modulating a totalamount of material sputtered off said sputter surface, said modulationarrangement being phase locked with said drive.
 31. The apparatus ofclaim 30, wherein said drive comprises one of a rotational pendulardrive that generates rotational pendulum movement and a rotational drivethat generates a rotational movement ofsaid magnet arrangement withrespect to an axis that is perpendicular to said sputter surface. 32.The apparatus of claim 30, wherein said modulation arrangement modulatesthe amount of sputtered off material per time unit simultaneously alongthe entire sputter surface.
 33. The apparatus of claim 30, wherein saidmodulation arrangement comprises at least one of a reactive gas flow anda working gas flow adjusting member.
 34. The apparatus of claim 30,wherein said modulation arrangement comprises an adjusting member for anelectrical feed ofsaid target.
 35. The apparatus of claim 30, whereinsaid magnet arrangement is shaped symmetrical to an axis which isparallel to said sputter surface.
 36. The apparatus of claim 30, whereinsaid magnet arrangement is shaped symmetrical with respect to twomutually perpendicular axes parallel to said sputter surface.
 37. Theapparatus of claim 30, further comprising a gas inlet that is positionedadjacent to said magnetron source, said gas inlet being connected to agas tank arrangement comprising a reactive gas.
 38. The apparatus ofclaim 30, wherein said target comprises a circular target.
 39. Theapparatus of claim 30, wherein said target is formed of a singlematerial.
 40. The apparatus of claim 30, wherein there is direct sightcommunication between said sputter surface and said substrate conveyorarrangement.
 41. The apparatus of claim 30, further comprising amonitoring arrangement that monitors a local distribution of materialdeposited on a substrate at said substrate conveyor arrangement, anoutput ofsaid monitoring arrangement being operationally connected to aninput of a comparing unit, a second input of said comparing unit beingoperationally connected to an output of a setting unit, an output ofsaid comparing unit being 1 operationally connected to a control inputof an adjusting unit of said modulation unit.
 42. The apparatus of claim30, wherein said conveyor arrangement is operationally connected to acyclical drive.